Quark-model relations among TMDs in the parton model

Abstract

The covariant parton model (CPM) is a consequent application of the parton model concept to the nucleon structure. In this model, there is a choice to put quarks either in a pure-spin state or in a mixed-spin state. We show that the mixed-spin version of the CPM does not support the quark-model relations among transverse momentum dependent parton distributions (TMDs) which were shown to hold in a large class of quark models. One can enforce the quark-model relations to be valid in the CPM by imposing a condition which is equivalent to putting the quarks in a pure-spin state. This gives a complementary perspective on the connection of the pure- and mixed-spin state CPM versions, and provides a fresh view on the question whether the quark-model relations could be realized in QCD as "approximate relations" with some useful numerical accuracy.

v1: 10 pages. v2: reformatted, 11 pages

References in corpus (17)

• Parton distributions for the LHC
• New parton distributions for collider physics
• Parton distributions in the LHC era: MMHT 2014 PDFs
• Evidence for polarization of gluons in the proton
• Relations between generalized and transverse momentum dependent parton distributions
• Transverse-momentum distributions in a diquark spectator model
• The transverse momentum dependent distribution functions in the bag model
• Azimuthal spin asymmetries in light-cone constituent quark models
• Pretzelosity $h_{1T}^{\perp }$ and quark orbital angular momentum
• Transverse momentum dependent distribution functions in a covariant parton model approach with quark orbital motion
• Are there approximate relations among transverse momentum dependent distribution functions?
• Naive time-reversal odd phenomena in semi-inclusive deep-inelastic scattering from light-cone constituent quark models
• The relation between TMDs and PDFs in the covariant parton model approach
• Phenomenology of NNLO jet production at the LHC and its impact on parton distributions
• Parton distribution functions and quark orbital motion
• Structure of the nucleon at leading and subleading twist in the covariant parton model
• Transversity and intrinsic motion of the constituents